Treatment for recycling fracture water gas and oil recovery in shale deposits

ABSTRACT

A method and apparatus for hydrocarbon recovery and/or treatment of frac water includes introducing a volume of water into a formation, recovering the introduced water, with the recovered introduced water further comprising suspended hydrocarbon product. The recovered liquid is treated to remove substantial amounts of the suspended hydrocarbon product, provide the treated recovered liquid with a ORP in a range of 150 mv to 1000 mv, and partially desalinated, and is either re-introduced as treated recovered liquid with the ORP into a formation to assist in recovery of additional hydrocarbon deposits in the formation, or is stored to reduce the ORP and then subsequently discharged into surface waters.

This application claims priority to U.S. Patent Application Ser. No.60/908,453, filed Mar. 28, 2007, entitled, “Gas and Oil Recovery inShale Deposits” the contents of which are incorporated herein byreference in their entirety.

BACKGROUND

This invention relates to shale based gas and oil recovery methods andfracture water treatment.

The gas industry has developed techniques to recover natural gas fromshale deposits by so called “horizontal fracturing.” In horizontalfracturing, a stream of water is injected under pressure into wellsdisposed through shale deposits. The fracturing process uses, e.g., from1 to 3 million gallons of water per fracture effort. Once the fracturingis completed, the water (i.e., “frac water”) is contaminated withpetroleum residue and is returned to holding tanks for decontamination.In the holding tanks, the return water settles layers comprising a clearpetroleum product, e.g., light non-aqueous phase liquids (LNAPL), whichare liquids that are nearly insoluble in water and less dense than waterand an underlying water product. For example, oil, gasoline, etc. areexamples of LNAPLs. This LNAPL, clear petroleum product, is normallydecanted off into tanks or a lined reservoir and sold to refineries as apetroleum product.

The underlying water layer is contaminated, e.g., by high concentrationsof alkanes, and may be somewhat saline. Generally, the underlying watercontains from 1 to 4 parts per thousand chlorides (10,000-40,000 ppm)after usage. Other ranges are of course possible based on environmentalconditions. Normally, drinking water standards generally require levelsless than 250 ppm chloride, in order to have proper viscosity fordischarge, whereas river discharge standards require generally levelsless than 2,000 ppm, although this standard can vary.

SUMMARY

According to an aspect of the invention, a method of hydrocarbonrecovery includes introducing a volume of water into a formation withthe water having an oxidation/reduction potential (ORP) of at leastabout 100 mv. in a range of 150 mv to 1000 mv.

The following are embodiments within the scope of the invention.

The formation includes shale deposits. The method includes treating avolume of water having suspended hydrocarbon product by exposing thevolume of water to ozone and/or a hydro-peroxide to produce the volumeof water having the ORP, with the ORP being in the a range of about 150mv to 1000 mv. The volume of water that is treated is frac-water that isrecovered from fracture operations in a formation having hydrocarbons.

The method includes exposing the recovered liquid to a fluid comprisingozone gas trapped in micro or nano size bubbles to provide the volume ofwater having the ORP in the a range of about 150 mv to 1000 mv. Themethod includes exposing the recovered liquid to a fluid comprisingozone gas trapped in micro or nano size bubbles and hydrogen peroxide toprovide the volume of water having the ORP in the a range of about 150mv to 1000 mv. The method includes exposing the recovered liquid to afluid comprising ozone gas trapped in micro or nano size bubbles ofhydrogen peroxide coated bubbles to provide the volume of water havingthe ORP in the a range of about 150 mv to 1000 mv.

According to a further aspect of the invention, a method includesreceiving water that was introduced into a earth formation, with thereceived, introduced water comprising suspended hydrocarbon product inthe water, treating the recovered water to remove substantial amounts ofthe suspended hydrocarbon product by exposing the recovered water toozone/air bubbles having a size less than 500 microns and to provide thetreated recovered water with a ORP in a range of 150 mv to 1000 mv andre-introducing the treated recovered water with the ORP into aformation.

The following are embodiments within the scope of the invention.

The formation includes shale deposits. The suspended hydrocarbon productcomprises alkanes and alkenes. Re-introducing includes re-introducingthe treated recovered water with the an ORP in a range of 150 mv to 1000mv into a the formation to assist in recovery of additional hydrocarbondeposits in the formation, recovering the re-introduced, treatedrecovered water, and treating the recovered re-introduced, treatedrecovered water to remove additional hydrocarbon product. The methodincludes exposing the recovered water to a fluid comprising ozone gas inbubbles having a size less than 200 microns. The method includesexposing the recovered water to a fluid comprising ozone gas in bubbleshaving a size less than 200 microns and hydrogen peroxide. The methodincludes exposing the recovered water to a fluid stream of microbubblesentrapping ozone gas in bubbles having a size less than 1 micron. Themethod includes exposing the recovered water to a fluid stream ofhydrogen peroxide coated microbubbles entrapping ozone gas in bubbleshaving a size less than 1 micron.

Re-introducing the treated recovered liquid with the ORP into aformation reintroduces the treated recovered water into the sameformation that the recovered water was recovered from. Re-introducingthe treated recovered water with the ORP into a formation reintroducesthe treated recovered water into a different formation than therecovered water was recovered from. The reintroduced, treated recoveredwater has an ORP in a range of 150 mv to 1000 mv.

According to a further aspect of the invention, an arrangement forhydrocarbon recovery includes a treatment tank that receives fracturewater, recovered in fracture recovery of hydrocarbon product from aformation, and treats the water to provide the water with an ORP in arange of about 150 mv to 1000 mv, the treatment tank including an inletthat receives the recovered fracture water, at least one chamber, adiffuser disposed in the chamber to introduce gaseous ozone and hydrogenperoxide into the fracture water, and an outlet configured to be coupledto a well that re-introduces the recovered water from the treatment tankinto a formation.

The following are embodiments within the scope of the invention.

The treatment tank is a baffled treatment tank, including a plurality ofbaffled chambers, with at least some of the chambers having a diffuserdisposed therein to deliver ozone and hydrogen peroxide to recoveredfracture water in the tank. The treatment tank is a baffled treatmenttank, comprising a plurality of baffled chambers, with at least some ofthe chambers having a nano-bubble generator disposed in the chamber todeliver nano-bubbles of ozone/air coated with hydrogen peroxide. Thearrangement includes a storage tank that receives the recovered waterfrom the treatment tank and stores it prior to the recovered water beingre-introduced into the formation.

The arrangement includes a storage tank coupled to the treatment tank,the storage tank receiving the recovered water extracted from theformation and stores the recovered water prior to the recovered waterbeing introduced into the treatment tank. The arrangement includes astorage tank, a treatment lagoon fluidly coupled to the storage tank,the treatment lagoon receiving the recovered water from the storage tankto treat the recovered water prior to the recovered water beingintroduced into the treatment tank.

According to a further aspect of the invention, a method of hydrocarbonrecovery includes introducing a volume of water into a formation,recovering the introduced water, with the recovered, introduced waterfurther comprising hydrocarbon product, treating the recovered water toremove portions of hydrocarbon product suspended in the water, byexposing the recovered water to a fluid stream of hydrogen peroxidecoated bubbles entrapping ozone gas, re-introducing the treatedrecovered water back into a formation and recovering additional waterfrom the formation with the additional water comprising additionalhydrocarbon product that was liberated from the formation.

The following are embodiments within the scope of the invention.

The suspended hydrocarbon product comprises alkanes and alkenes. Thebubbles have a diameter in a range of about 0.05 microns to about 200microns. The method includes pre-treating the recovered introducedliquid to remove substantial portions of hydrocarbon product leavingsubstantially suspended hydrocarbon product in the liquid.

According to a further aspect of the invention, a method of treatingfracture water includes recovering introduced liquid from a formation,the recovered introduced liquid comprising suspended hydrocarbonproduct, treating the recovered liquid to remove substantial amounts ofthe suspended hydrocarbon product, in part by, exposing the recoveredwater to bubbles trapping air/ozone with the bubbles having a bubblesize in a range of 0.05 to 200 microns.

The following are embodiments within the scope of the invention.

Treating includes allowing the recovered liquid to be held to permitlighter product to be skimmed off of the product, prior to exposing thewater to the bubbles. The suspended hydrocarbon product comprisesalkanes and alkenes. Treating includes holding the recovered liquid topermit heaver constituents to settle from the recovered liquid. Treatingincludes allowing the recovered liquid to be held to permit lighterproduct to be skimmed off of the product, and holding the recoveredliquid to permit heaver constituents to settle from the recovered liquidprior to exposing the recovered liquid to a fluid comprising ozone gasand hydrogen peroxide. Treating includes exposing the recovered liquidto a fluid stream of hydrogen peroxide coated microbubbles entrappingozone gas. The recovered liquid after treatment by the ozone isessentially water that can be discharged into surface waters. Deliveringthe treated, recovered liquid after treatment by the ozone to a holdingarea to reduce the ORP until the water can be discharged.

An treatment tank includes a vessel to receive contaminated water and totreat the water, the vessel having walls to form an enclosure andincluding an inlet to receive contaminated water. The tank also includesa plurality of chambers that are partitioned in the vessel by bafflewalls that extend between two opposing sides of the vessel with a firstgroup of the baffle walls having a portion that extends above thesurface level water and a second group of the baffle walls having bottomportions that are displaced from a bottom surface of the vessel,diffusers disposed in the chambers to introduce a gaseous and liquidinto the chambers, and an outlet.

The following are embodiments within the scope of the invention.

The diffusers are disposed to deliver ozone and hydrogen peroxide tocontaminated water in the vessel. At least some of the chambers having ananobubble generator disposed in the chamber to deliver nanobubbles ofozone/air coated with hydrogen peroxide. The arrangement includes ananobubble generator disposed as the inlet to the vessel. Some of thebaffles have a spill-way portion on the top of the baffles that extendabove the water line level. Some of the baffles have a spill-way portionon the bottom of the baffles that are displaced from the bottom of thevessel.

One or more aspects of the invention may provide one or more of thefollowing advantages.

The techniques separate out product, treat resulting underlying water(aqueous) fraction, remove a fraction of saline (chlorides), and returnwater for reuse at quality of surface water discharge conditions.Additionally the techniques use treated frac water having a level ofreactivity and re-introducing the frac water into a new or existing wellhole to dissolve paraffins and other constituents to assist withsecondary and tertiary release and recovery of hydrocarbon product fromthese and other petroleum deposits. The treated frac water having alevel of reactivity (e.g., elevated oxidation-reduction potential (ORP))can be used with or without conventional surfactants for enhancedhydrocarbon recovery from shale and like deposits. The elevated ORP aidsin dissolving of paraffins, whereas introduction of nanobubbles underelevated pressures result in collapse of bubbles with a concomitantrelease of energy that aids in fracturing and paraffin reduction.

Ozone has shown a high affinity to attack alkane fractions. Inlaboratory testing and field trials, as the ozone concentration has beenincreased and the size of microbubbles decreased to below micron levels,the efficiency of reactivity has increased to the level beginning toexceed the normal ratio of 1 to 3 molar, or ⅓ of the ozone moleculesbeing involved, common to normal ozone molecular reactions where onlythe terminal oxygen inserts. It has been thought that secondarybiological (bacterial) reactions may be responsible for the ratioapproaching 1 to 1 on a mass to mass basis. However, I now believe thatthere is sufficient basis from laboratory tests to define a newerreactive form of ozone which has become apparent as the bubble sizemoves from micron size to nano size diameters.

This may prove particularly capable of removing petroleum chain productsand to treat sewage effluent since the long-chain fatty products areknown as the common clogger of leaching fields.

According to an additional aspect of the invention, the inventionprovides a new form of reactive ozone and techniques for producingnanobubble suspensions.

According to a further aspect of the invention, a method includes amethod includes forming bubbles having a submicron radius, the bubblesentrapping a high concentration of ozone, with the ozone orienting a netnegative charge outwards and a net positive charge inwards.

According to a further aspect of the invention, a method, includesdelivering ozone gas to a diffuser that emits bubbles having a diametersubstantially less that 1 micron and selecting conditions under whichthe ozone gas emanates from the diffuser, entrapped as a gas in thebubbles and having an orientation of negative charge on the surface ofthe bubbles.

According to a further aspect of the invention, a method includes adiffuser including a casing, a bubble generator disposed in the casingand a stirrer disposed at an egress of the casing.

According to a further aspect of the invention, a panel includes anozone generator, a controller, a metering gas generator/compressor, anda nano bubble solution generator.

According to a further aspect of the invention, a discharge tube is fedby a nano bubble solution generator in which is disposed an acousticprobe at the end for dissemination of the reactive liquid.

One or more advantages can be provided from the above.

The treatment techniques can use bubbles, bubbles with coatings, anddirected sound waves to treat volatile organic compounds (VOCs),pharmaceuticals, and other recalcitrant compounds found in drinkingwater, ground water, sewage, and chemical waste waters. Nano scalereactions should allow a three to tenfold increase in efficiency ofreactions which will significantly improve treatment, e.g., reduction ofresidence contact time, reduction of column height for treatment, etc.

The new, reactive form of ozone is manifest as a nanoscale film. Thearrangements combine new reactive ozone species with dissolved ozone,suspended with nanoscale gaseous ozone. Sonic vibration can be used torestructure the ozone bubbles to allow for sonic vibration of thenanoscale spherical film surfaces to further increase selectivity andreactivity. The addition of coatings of peroxides further enhancesreactive radical production of hydroxyl and perhydroxyl species furtherimproving reaction rates.

With an ex-situ system, the generation of suspended homogenized micro tonanoscale-sized ozone bubble solutions allowing the flow of the reactiveliquid into a treatment container (ozone tank or sump) without concernfor fouling of a membrane or microporous surface during gas generation.The generator can be supplied with filtered tap water (normallyavailable with 50 psi pressure), an ozone generator, and small pump withhouse current (120V) and housed in a simple container for application.

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and the description below. Other features,objects, and advantages of the invention will be apparent from thedescription and drawings, and from the claims.

DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram of an arrangement for horizontal fracturingwith treated water.

FIG. 2 is a block diagram of a water treatment arrangement.

FIG. 3 is a block diagram of details of the treatment arrangement.

FIGS. 4A-B and 5A-B are diagrams of a baffled treatment tank.

FIG. 6 is a block diagram of an alternative baffled treatment tankarrangement.

FIG. 6A is a diagram of a venturi type of nozzle for water inlet in thearrangement of FIG. 6.

FIG. 7 is a block diagram of an alternative treatment arrangementsuitable for use with the arrangement of FIG. 6.

FIG. 8 is a block diagram of an alternative arrangement for horizontalfracturing and/or discharge of treated water.

FIG. 9 is a cross-sectional view showing a sparging treatment system.

FIG. 10 is a cross-sectional view showing a sparging treatment systemwith well screen and a multi-fluid diffuser.

FIG. 11 is a longitudinal cross-section view of a multi-fluid diffuseruseful in the arrangement of FIG. 9.

FIG. 12 is a longitudinal cross-section view of an alternativemulti-fluid diffuser useful in direct injection into shallow contaminantformations.

FIGS. 13A and 13B are cross-sectional view of sidewalls of themulti-fluid diffuser of FIGS. 3 or 4 showing exemplary constructiondetails.

FIG. 14 is a diagrammatical plan view of a septic system.

FIG. 14A is a schematic, elevational view of the septic system of FIG.14.

FIG. 14B is a blown up view of a portion of FIG. 14A.

FIG. 15 is a diagrammatical, longitudinal cross-section view of analternative multi-fluid diffuser useful in the arrangements of FIGS. 1,2 and 6.

FIG. 15A is a blown up view of a portion of FIG. 15.

FIG. 16 is a view showing a detail of a ozone treatment chamber and themulti-fluid diffuser of FIG. 15.

FIGS. 17 and 17A are diagrammatical views representing a structure ofozone.

FIG. 18 is a schematic of a nanobubble generator.

DETAILED DESCRIPTION

Referring to FIG. 1 an arrangement 10 for recovery of hydrocarbons inearth deposits, such as shale 12 is shown. The arrangement can be usedin other deposits that have hydrocarbons, such as tar sands and soforth. Tar sands are often used to refer to bituminous sands, oil sandsor extra heavy oil deposits. Tar sands include sand or/and clay, water,and extra heavy crude oil. The arrangement 10 includes the injection ofwater under pressure. Wells 14 are drilled into, e.g., shale and arediverted horizontally and then holed by special down-well tools to allowthe fluid to fracture the shale horizontally. The fluid, e.g., water isinjected with beads (propagent) to hold the channels open afterfracturing. A single well normally yields return fluids water andproduct of up to 60% of injected water or more. The arrangement 10includes conventional horizontal well fracture apparatus 11, and atreatment apparatus 30 that will be described in FIG. 2. Otherfracturing techniques could be used.

The arrangement 10 includes a plurality of horizontal wells 14, asshown. A first one of the horizontal wells 14 is used to deliver afluid, e.g., water 20 under pressure to shale 12 that lies below thesurface. For this first one, the water is typically water that comesfrom, e.g., a river and so forth. The water 20 under pressure is used tofracture the underlying shale formations causing fracture pathways inthe shale to allow for extraction of hydrocarbon product that is trappedin the shale. The same borehole is used to recover e.g., 60% of theinjected water which rebounds under pressure, (e.g., the water isinjected under pressure sufficient to lift the soil weight above it(fracturing)). When the source pressure is removed, the formation weightcollapses on the fracture, pushing the water back up the pipe underconsiderable pressure. The original fracture well 14 is used to recoverthe water 22 that was introduced under pressure. This water 22 iscommonly referred to as fracture water or “frac-water.” The frac water22 is contaminated with, e.g., homogenized, hydrocarbon product, as wellas other products. The water 20 is supplied from a supply (not shown)and is pumped under very high pressures into the formation via acompressor. Often many thousands if not millions of gallons of water areintroduced to fracture the underlying shale.

The arrangement 10 includes at least a second other horizontal well 14,as shown. The second horizontal well 14 is used to deliver a fluid,e.g., water 21, comprised of “make up” water 20 a (make-up referring tothe volume of water that was not recovered from the first well 14 andthat needs to be added to the second well) under pressure that iscombined with so called “treated water 30 a” that comes from treatmentapparatus 30, to the shale 12 that lies below the surface. The water 21under pressure is used to fracture the underlying shale formationscausing fracture pathways in the shale to allow for extraction ofhydrocarbon product that is trapped in the shale, as before. However,the water 21 because it includes the treated water 30 a has an elevatedORP that can be used to advantage to dissolve paraffin that can inhibitrelease of hydrocarbon product. The same borehole in the second well 14is used to recover again over 60% of the injected fluid, e.g., water,(and hydrocarbon product) which rebounds under pressure. The frac water24 from the second well 14 is again contaminated with hydrocarbonproduct, which would in general be a higher percentage of hydrocarbonproduct than the first well that did not use the treated water 30 a withthe elevated ORP, as well as other products. It can be treated anddischarged or treated and re-injected into a subsequent well.

In addition, the arrangement 30 with a single one of the wells 14 can beused for treatment (without re-injection) but rather discharge, as alsodiscussed below.

Referring now to FIG. 2, a treatment system 30 for treatment of“frac-water,” e.g., the extracted water 22 or 24 used in fracturing theshale deposits, and which is used to provide the treated water 30 a, forsubsequent fracturing or for discharge is shown. The system 30 includesproduct separation treatment tanks 32, a settling lagoon 34 (or storagetanks), and a pump 36. The pump transfers liquid from the settlinglagoon 34 or other storage tanks to a chemical oxidation treatmentsystem 40 for removing VOCs (volatile organic compounds) and TOC (totalorganic carbon), heavy metals, (e.g., Fe, Mn, etc.) and to adesalination unit 48 for salt removal.

As mentioned, the extracted frac-water 22 from the formation comprises“product”, e.g., light non-aqueous phase liquids (LNAPL) and anunderlying water product. The frac-water 22 is allowed to separate intothe LNAPL and underlying water in the product separator and initialstorage tanks 32 where substantial LNAPL product, e.g., are skimmed offof the surface of the recovered frac-water. This product is typicallysold and used for various purposes. An exemplary analysis of a typicalproduct is:

Product: Petroleum Hydrocarbons C8 to C30 (Similar to aviation/jet fuel)Contains: Toluene .019 Xylenes .045 (est.) Benzene .009 (est.)Ethylbenzene .007 (est.) Trimethylbenzene .018 (est.) Acetone .005 (est.from aqueous fraction by proportion) TPH 70% alkanes C6 to C30 15% VOCs(BTEX, etc.) No PAHs found SVOCs ND (None detected) Alkanes/AlkenesPetroleum Hydrocarbons GC-GRO Gasoline-range organics 380,000 μg/LGC-DRO Diesel-range organics 182,000 μg/L Metals (in aqueous) Copper,total .041 mg/L Iron, total   11 mg/L Lead, total ND Manganese, total1.84 mg/L Zinc, total .072 mg/L

The liquid that remains is generally an emulsion including water andother hydrocarbon products. An exemplary analysis of a typical aqueousfraction, which was part of the frac-water from the product analysisabove, is:

Aqueous Fraction: VOCs (μg/L) Benzene 370 Toluene 1800 Ethylbenzene 230p/m Xylene 2600 o Xylene 540 Acetone 1100 n-Butylbenzene 140sec-Butylbenzene 41 Isopropylbenzene 63 p-Isopropyltoluene 84n-Propylbenzene 98 1,3,5 Trimethylbenzene 920 1,2,4 Trimethylbenzene1000 SVOCs ND (Nondetect) Alkanes/Alkenes Petroleum Hydrocarbons GC-GROGasoline-range organics 380,000 μg/L GC-DRO Diesel-range organics182,000 μg/L Metals (in aqueous) Copper, total .041 mg/L Iron, total  11 mg/L Lead, total ND Manganese, total 1.84 mg/L Zinc, total .072mg/L

This emulsion is fed to the settling lagoon 34 (or a large tank) wheresemi-volatile organics and metals particulates settle out.

From the settling lagoon 34 the aqueous fraction still comprises organichydrocarbons that are in an emulsion or suspension. The liquid from thesettling lagoon 34 is fed to a pump 36 that pumps the liquid into theoxidation treatment system 40.

The chemical oxidation treatment system 40, an exemplary, detailedembodiment of which is discussed in FIG. 3, includes an ozone/peroxideapparatus 42 that feeds streams of air/ozone/hydrogen peroxide todiffusers 43 disposed in a baffled treatment tank 44. The diffusers 43can be of any type but preferably are laminar microporous diffusers orLAMINAR SPARGEPOINTS® from Kerfoot Technologies, Inc. Mashpee Mass., asdescribed in U.S. Pat. No. 6,436,285 incorporated herein by reference inits entirety.

The contaminated water is removed from the baffled treatment tank 44, isfiltered to remove metal precipitates 45, partially desalinated 46, andis allowed to reside in a storage tank 48 for a period of time, e.g.,1-2 months, for discharge in surface waters or less than 2 weeks (orimmediately) for re-induction into a new drill hole to break downparaffins and other materials to increase hydraulic conductivity. Theseparaffins and other materials tend to clog fractures in the formation.Previous attempts to remove these include addition of surfactants.Surfactants can be used with the treated water. Off-gas from the baffledtank containing residual ozone, carbon dioxide, and air is sent throughcatalyst (carulite) for treatment 44 a.

Referring now to FIG. 3, a detailed example 60 of the ozone/peroxideapparatus 42 (FIG. 2) that is part of the chemical oxidation treatmentsystem 40 (FIG. 2) is shown. The ozone/peroxide apparatus 42 includes anozone generator, timer/controller 64, compressor/metering 66, solenoids68, and lines 70 and a distribution manifold that distributes pluralflows of a liquid oxidant such as hydrogen peroxide and ozone/air toplural diffusers 43 that reside in baffled treatment tank. Details onvarious configurations for ozone/peroxide apparatus 42 are described inthe above application. Other configurations are disclosed in U.S. Pat.No. 6,582,611(B1) also incorporated herein by reference in its entirety.

Typical specifications for the operation of the system are set outbelow:

Organic Treatment Unit Characteristics and Specifications Water flow:60,000 gallons/day (2,500 gal/hr) Volume: 10,560 gallons Residence time:4 hours Ozone requirement: 1 to 1 (O₃/carbon) Contaminant level: GoalsVOCs: 2000 μg BTEX <20 μg BTEx Alkanes: 500 mg TPH <10 mg Ozone demand:25 lbs/day (cooling H₂O may or not be required depending on localconditions) Compressor: 50-200 cfm Oxygen Generator: 3.5 scfm Peroxidetank: 300 gallon (10%) Peroxide pump: .01 to .2 gallons/minuteOzone/peroxide ratio: 1 to 2 (molar) Ozone concentration: 500 to 5000ppmv Gas (air/ozone) to water 5 to 1 volume ratio:

An example of a baffled treatment tank is disclosed in U.S. Pat. No.6,436,285 which is incorporated herein by reference in its entirety.

An alternative example is shown in FIGS. 4A-4B, the details of thecoupling of the microporous diffusers 43 in the tank 44 being omittedfor clarity in these figures, but exemplary connection arrangements areshown in FIGS. 5A and 5B. In this example, the baffled treatment tank 44has a vessel or body portion 44 b generally here rectangular, and hasbaffles 44 a that are displaced in a vertical dimension to permitcirculation down one chamber and up an adjacent chamber, as shown inFIGS. 5A and 5B.

The treatment tank thus includes, in addition to the vessel 44 b, aninlet 45 a to receive contaminated water and a plurality of chambersthat are provided as partitions in the vessel by the baffle 44 a thatextend between two opposing sides of the vessel 44 b with a first groupof the baffles 44 a having a portion that extends above a surface levelof the water and a second group of the baffles 44 a having bottomportions that is displaced from a bottom surface of the vessel 44 b.Diffusers 43 are disposed in the chambers to introduce a gaseous andliquid into the chambers and the vessel includes an outlet. As will bediscussed below, in some embodiments, some or all of the chambers have ananobubble generator disposed in the chamber to deliver nanobubbles ofozone/air coated with hydrogen peroxide. As will be also discussedbelow, a nanobubble generator can be disposed as the inlet 45 a to thevessel.

The baffles have a spill-way portion on the top of the baffles thatextend above the water line level or a spill-way portion on the bottomof the baffles that are displaced from the bottom of the vessel.

The baffled tank 44 also includes an outlet 45 b and in some embodimentsa top cover member 44 c so that the water is introduced into the tank 44under pressure, e.g., typically less than 20 psi. In other embodimentsthe tank can be open and not operate under pressure.

Other arrangements are possible, as will be discussed below.

From the baffled treatment tank 44, the water at an outlet 45 b may befiltered for metal removal, stored and/or sent for desalinization, ifthe water is saline. Generally, the water contains about 40 parts perthousand chlorides (40,000 ppm) after usage and decontamination by theair/ozone/hydrogen peroxide. If the water is somewhat saline aftertreatment by the air/ozone/hydrogen peroxide the water can bedesalinized via an ultra-filtration reverse osmosis/(RO) salt removalfilter 48, (FIG. 2) to remove salt to below contact or drinking waterstandards e.g., 250 to 1000 ppm chloride, or for river discharge, e.g.,less than 2000 ppm, or recharge for fracturing, e.g., less than 20,000ppm, as necessary.

Referring now to FIG. 6, an alternative arrangement for a baffled tank44′ includes a nanobubble generator 70 disposed at the entrance of thebaffled tank 44′ that provides an inlet that receives recovered fracturewater and an outlet 71 b that delivers treated, recovered fracturewater. The baffled tank can also have a second inlet (not shown). Thenanobubble generator 70 in combination with a plurality of cylindricalnanobubble generators 72 disposed within corresponding ones of baffledcompartments 73 adjacent baffles 74 of the tank 44′ provide nanobubblesof gas entrapped by coated bubbles. The nanobubble generators 70 and 72are described in my co-pending U.S. patent application Ser. No.11/516,973, filed Sep. 7, 2006 entitled “Enhanced Reactive Ozone” andincorporate herein by reference in its entirety and as discussed below.Each of the nanobubble generators 70 and 72 are fed air/ozone andhydrogen peroxide flows, as illustrated for an exemplary one of thenanobubble generators 72 from a manifold 75 or other distributionarrangement. The nanobubble generators 72 are mounted on the side of thebaffles 74 and inject hydrogen peroxide coated nanobubbles of air/ozoneinto the flow stream. The air/ozone/hydrogen peroxide decontaminates thewater by decomposing alkanes that are in the water leaving asbyproducts, e.g., acetone, alcohol, carbon dioxide, water, and reactivehydro-peroxides with nanobubbles, that retain the reactively of thesolution. In this embodiment, the tank 44′ is a covered tank thatoperates under pressure, e.g., 20 psi, and thus includes a pressurerelief valve 78. In other embodiments, the tank need not be pressurizedor other pressures could be used.

Referring now to FIG. 6A, an example of the nanobubble generator 70 isshown.

The nanobubble generator 70 is of a venturi type, having inlets 70 a-70c for gas, water and peroxide, respectively, and an outlet 70 d fordelivery of coated nanobubbles. An inner tube 71 a of nanoporousstainless steel, having successively increasing internal cross sections,as shown to provide a venturi effect is surrounded by a micron glassbead pack 70 b that is confined between the tube 71 a and a microporoustube 71 c. A gap 71 d is provided between the microporous tube 71 c andan outer casing 71 e. Other arrangements are possible. For instance, onesuch arrangement is described in my issued U.S. Pat. No. 6,913,251,entitled “Deep Well Sparging.”

Referring now to FIG. 7, a treatment arrangement suitable for use withthe tank of FIG. 6 is shown. The nanobubble generator 70 (similar tonanobubble generator 350 (FIG. 18) that can be deployed in fieldoperations is shown. The nanobubble generator 150 includes an ozonegenerator 152 fed via, e.g., dry air or oxygen, a nanobubble solutiongenerator 154 fed liquid, e.g., water or hydrogen peroxide and ozone/airor ozone/oxygen from a compressor 156. Liquid is output from thenanobubble solution generator 154 and includes a cloud of nanobubbles,and is delivered to a bank of solenoid controlled valves 158 to feedtubes 72 that can be disposed in the contact tank (FIG. 6). The feedtubes 72 can have acoustic or sonic probes 123 disposed in the tips, asshown. A controller/timer 153 controls the compressor and solenoidcontrol valves. A excess gas line 155 is connected via a check valve 157between nanobubble solution generator 154 and the line from the ozonegenerator to bleed off excess air from the nanobubble solution generator154. A pump is used to deliver the liquid here through a flowmeter withoptional oscillator.

The high concentration of alkanes/alkenes and VOCs are treated bytechniques that produce nano to micro size bubbles including ozone andoxygen as oxidizing gases entrapped by water and having a liquid coatingof a hydroperoxide, e.g., hydrogen peroxide.

In particular, the use of nanobubbles provides a spherical arrangementof ozone, as described in my co-pending application entitled: “EnhancedReactive Ozone” mentioned above. The spherical arrangement of ozoneprovides a nano-microbubble distribution that is negatively charged,changing the local surface tension, of the bubble attracting hydrophobicmolecules by charge and Henry's partitioning constant from aqueous togaseous phases. The film regions of the bubbles are highly reactiveregions, continually generating hydroxyl and related radicals capable ofdecomposing the hydrocarbon fractions into small segments which may, inturn, more quickly react with other bubbles surfaces.

The nano to micro bubble generators are configured to both reduce thesize of the bubbles, and narrow the range of sizes of the bubbles in thebubble populations. The decrease in size of the bubbles may increase thereactive strength and longevity of the bubbles in the water, thusmaintaining the highly reactive form of ozone in water for relativelyhigh lifetimes. In some embodiments, the remaining water is rechargedback into fracture wells or retained in storage for return to streams.Thus, the treated water, depending on saline condition, is may bedischarged into a river or discharged onto or into land.

However, the treated water, immediately after treatment with ozone andor ozone/peroxide and prior to storage, is reactive, e.g., having anelevated, oxidation reduction potential of at least 100 mv and generallyin the range of about 150 to 1000 mv or more, and containing amilky-like suspension of nano to microbubbles of similar size. Subjectedto re-injection, under pressure, the bubbles may collapse and provide aconcomitant release of high levels of chemical energy.

The use of nano-micro size bubble generators produces nanobubble sizesthrough the properties of charged ozone and peroxide films that modifysurface tension and allow such fine bubbles where normally highpressures (200 psi) would be necessary to produce them (if air ornitrogen gas were used). Under fracture well re-injection pressures(>200 psi), the bubbles may collapse. The nano-size micro-size bubblegenerator produces bubbles having a relatively narrow range of sizes ofsuch nanobubbles. This provides a mechanism analogous to a radioactivechain reaction where most of the bubbles being of similar, relativelysmall size all collapse in a very rapid sequence. Extreme compression,(as would occur by injection into deep wells or under the influence ofan acoustically-focused beam) initiates a collapse of a significantfraction of the population of bubbles. A resulting compression wavecaused by the collapse, would initiate compression of neighboringbubbles. The estimated heat of energy released upon collapse could besignificant. Weavers, L. et al. (1998) suggested thatO₃→O₂+O(3p)O(3p)+H₂O→2OH.

With Pentachlorophenol, invading the gas bubble, C_(p)=201 Jmol⁻¹K⁻¹.With these chemical energies, the re-injected fluid would not needsurfactant to rapidly remove paraffin fractions that retard eitherliquid or gas flow in, e.g., fractured shale.

In the chambered baffle tank, the water is subject to pulsed pressureflow of ozone-air gas (up to, e.g., 20 psi). The nano to microbubblesare formed by introducing the oxidizing gas as an air-ozone stream alongwith introducing a liquid including hydrogen peroxide through, e.g., alaminar Spargepoint® (Kerfoot Technologies, Inc. Mashpee Mass.) or asseparate flows to provide the coating of hydrogen peroxide over thebubbles. The bubbles have a diameter of less than e.g., 0.05 microns upto about 200 microns, e.g., 0.05 to 80 microns, 0.1 to 20 microns, andso forth. With the nanobubble generator 150, the range of sizes in thebubbles is narrower.

The ozone gas can be introduced in a cyclic ring form (O₃)_(n), where nis the number of ozone molecules within a polar ring structuresurrounded by a generally sub micron bubble as disclosed in myco-pending U.S. patent application Ser. No. 11/516,973 entitled“Enhanced Reactive Ozone” mentioned above. With hydroperoxide coatedmicrobubbles the nanobubble configuration of the outer film is thecyclic ring form (O₃) (H₂O₂)_(n), where n is the number of ozone andperoxide molecules within the polar ring structure. For a sphericalarrangement, the corresponding equations would be (O₃)_(n) ⁻RCOSØ forozone alone,

Where:

R=radius of bubble

Ø=angle in 3 dimensions

and

n=number of polarized ozone molecules around circumference

(O₃)⁻=polarized ozone molecule

and (O₃)_(n) ⁻(H₂O₂)_(n) ⁻RCOSØ for peroxide as a hydroperoxide.

Where:

R=radius of bubble

Ø=angle in 3 dimensions

n=number of polarized ozone an peroxide molecules around circumference

(O₃)_(n) ⁻(H₂O₂)_(n) ⁻=polarized ozone/peroxide pair

The organic-contaminated water comprises primarily petroleumhydrocarbons including alkanes and alkenes. With enhanced reactive ozoneand peroxide coating, the stoichiometric ratio of ozone to carboncompound (C₄ to C₃₀) mineralized approaches a ratio less than 3.0. Thestoichiometric ratio of ozone to carbon compound (C₄ to C₃₀) mineralizedapproaches a ratio of 1.0 to 1.0. The ozone/oxygen gas is pulsed with apressure of 0 to 50 psi by a peristaltic or piston pump. The peroxide ispulsed with a pressure of 0 to 50 psi by a piston or peristaltic pump.

The frequency of pulsing varies from 1 to 60 times per hour.Alternatively, the frequency of pulsing varies from 1 to 60 times perminute. Other frequencies are possible. With the nanobubble generatorsthe Laminar point configuration is placed in a pressurized tube, and amagnetic spinner is used to achieve shear velocities along the micro tonanoporous surface. Suspended beads or angular particulates may also berotated in solution to shear off emerging bubbles and achieve smallsize. The hydrogen peroxide coating on the microbubbles promotesdecomposition by adding a secondary liquid phase reactive interface asvolatile compounds enter a gaseous phase.

After removal of VOC compounds and total organic carbon, filtration isdone to separate out suspended metals, like fine iron flocculation.Nanobubbles however still persist. The water stream is separated fordesalination. Ultrafiltration protects the reverse osmosis unit frombeing attacked by the nanobubbles. The recombined waters can be recycleddown wells or held.

During reintroduction of the treated frac water back into the ground,residual hydroperoxide content of the recharged water continues to reactwith weathered paraffins to enlarge fracture zones and remove fattyparaffin deposits, liberating additional trapped hydrocarbon product,oil and gas in the ground for recovery and use. Residual acetone andhydroperoxide content of the recharged water improves hydraulicconductivity over untreated water injection.

Treatment Example

A bench scale test was performed on groundwater samples of fracturewater. Upon receipt of the samples, they were kept refrigerated untiltesting began. The purpose of the tests was to evaluate the effects ofchemical oxidation on the primary contaminants of concern (COCs):alkanes (GRO), BTEX, and other volatile compounds. Each test includedsubjecting groundwater contained within a pressure reaction vessel tovarious injected concentrations of the oxidants ozone and hydrogenperoxide for a period of 180 minutes (3 hrs).

Procedure

Following receipt of the concentration of COCs, injected ozoneconcentrations were calculated in order to achieve a minimal total molarconcentration near the molar concentrations of the COCs. This was doneto increase the plausibility of measuring a significant change of massreductions of the COCs between the two tests. Each enhanced reactiveozone/peroxide test was conducted in a 2-liter glass reaction celloutfitted with a laminar Spargepoint®, temperature probe and sampleport. During each test, a stir bar constantly set to 7, was used tosuspend and mix the soil in the groundwater. During each test thereaction vessel was under 5 psig of pressure, sparged gases wereinjected at a rate of 500 mL/minute, and, two liters of groundwater weretreated.

The table below has a summary of test parameters and laboratoryanalyses. Prior to starting each test, groundwater samples were obtainedat the start in order to identify starting concentrations, providesimilar stoichiometric and oxidation demands between the two tests.Groundwater was allowed to come to room temperature prior to startingthe tests to eliminate temperature differential reaction effects. Eachtest was run for 180 minutes and included a starting stirred solution of2 liters of homogenized groundwater. Initial (t₀) groundwater sampleswere taken. Following the completion of each test, treated groundwaterwas collected and immediately containerized according to the type ofanalyses to be conducted. Following containerization of all groundwatersamples, they were immediately cooled/refrigerated to 40° F. untiltransport to the laboratory. The reaction vessel was decontaminatedbetween each test by rinsing with a hot soapy solution followed byseveral rinses with distilled water.

Results

Bench scale test laboratory results indicate significant reduction inCOCs from groundwater in both tests. Specifically, the tables belowsummarizes analytical findings, mass changes, mass removals, andpercentage mass removed as a result of each test. Reviewing these datasuggest the following:

The most efficient groundwater mass reduction of the COCs occurred as aresult of the performance of test #1 (ozone @ 1,500 ppmV and peroxide @10%): An approximate range of 88% to 96% mass of the Gasoline RangeOrganics (GRO) were removed; 99+% of the BTEX and related VOCs wereremoved. A slight rise in acetone occurred. The mean value lies justbelow the permissible level for surface water discharge.

Ideally, the decay curves indicate a reaction time of 4 hours wouldyield values equal to or less than guidelines for discharge of organicsto general surface waters (no floating product, emulsified oil andgrease—less than 10 mg/L, with VOCs and SVOCs below detectable levels.

The Table I of bench-scale results is set forth below along with theoriginal characterization Table II of the fracture wastewater andfloating (NAPL) product. Of interest, after 3-4 days of standing, thevials became clear (FIG. 1) with a small heavier-than-water (DNAPL)precipitating out. Analytical review of the less than 0.05% DNAPL,colored red, suggests a high weight heavy paraffin, probably over 40carbon. This can be filtered out, normally using 45 micron bag-likefilters. The heavier paraffins, like candle wax are not considered ahealth problem organic.

TABLE 1 Fracture Water Bench-Scale Test, 2-Liter Aqueous Sample Start 1Hr. 2 Hr. End (3 Hr.) 1500 ppmv ozone, 2 ml/min 10% peroxide, 5 psi VOCs1FW1 1FW2 1FW3 1FW4 Benzene 360 ND ND ND Toluene 2400 200 ND NDEthylbenzene 460 53 ND ND Xylenes p/m-xylene 5000 380 120 ND o-xylene1100 150 120 ND 1,3,5 Trimethylbenzene 2100 ND(<250) ND ND 1,2,4Trimethylbenzene 2200 ND(<250) ND ND Isopropylbenzene 140 ND(<50) ND NDp-Isopropyltoluene 200 ND(<50) ND ND n-Propylbenzene 240 ND(<250) ND NDAcetone 1100 2100 2600 2000 GRO 180,000 120,000 57,000 22,000 6000 ppmvozone, 2 ml/min 10% peroxide, 5 psi 2FW1 2FW2 2FW3 2FW4 Benzene 310 80ND ND Toluene 160 450 ND ND Ethylbenzene 240 75 ND ND Xylenes p/m-xylene2600 790 150 ND o-xylene 570 210 ND ND 1,3,5 Trimethylbenzene 550 ND NDND 1,2,4 Trimethylbenzene 1100 360 ND ND Isopropylbenzene 70 ND ND NDp-Isopropyltoluene 90 ND ND ND n-Propylbenzene 110 ND ND ND Acetone 11002700 2500 2100 GRO 280,000 100,000 38,000 12,000

TABLE II Analysis: Product and Aqueous (water) Fraction AnalyzedProduct: Petroleum Hydrycarbons C8 to C30 (Similar to aviation/jet fuel)Contains: Toluene .019 Xylenes .045 (est.) Benzene .009 (est.)Ethylbenzene .007 (est.) Trimethylbenzene .018 (est.) Acetone .005 (est.from aqueous fraction by proportion) TPH 70% alkanes C6 to C30 15% VOCs(BTEX, etc.) No PAHs found Aqueous Fraction: VOCs (μg/L) Benzene 370Toluene 1800 Ethylbenzene 230 p/m Xylene 2600 o Xylene 540 Acetone 1100n-Butylbenzene 140 sec-Butylbenzene 41 Isopropylbenzene 63p-Isopropyltoluene 84 n-Propylbenzene 98 1,3,5 Trimethylbenzene 9201,2,4 Trimethylbenzene 1000 SVOCs ND (Nondetect) Petroleum HydrocarbonsGC-GRO Gasoline-range organics 380,000 μg/L GC-DRO Diesel-range organics182,000 μg/L Metals (in aqueous) Copper, total .041 mg/L Iron, total  11 mg/L Lead, total ND Manganese, total 1.84 mg/L Zinc, total .072mg/LPilot Testing

Test runs were conducted on fracture water hauled to a pilot testsystem. The total dissolved solids (TDS) ranged from a high of 40,000mg/L to a low of 8,700 mg/L. The mean value of all samples (measured asspecific conductance, converted to TDS equivalents) was 20,694 mg/L.Five of the twelve samples fell above, while seven fell at or below20,000 mg/L TDS. While salinity adjustment may be needed, a seawatertreatment system should be adequate and could be made to operate only asneeded for final polishing (to less than 20,000 mg/L TDS) summarized inTable III below.

Treatment efficiency in the pilot testing confirms the observedbench-scale efficiencies, discussed above. Organic removal was about94-98% removal. Because the TPH (total petroleum hydrocarbons) isrunning in the thousandths instead of hundred thousandths of ug/L,reduction to less than 200 μg/L was common. Benzene has also beenreduced below MCLs in a number of cases. Considering the pickup inefficiencies expected with stainless steel nano to micro Laminar points,the volume flow may be able to be increased to, e.g., 80,000 gpd(gallons per day) instead of 60,000 gpd.

The lower mean organic mass obtained by drawing liquid below tank topsand after oil/water separation can reduce the requirement for peroxideflow. Some of the lower values are treatable with ozone alone. An FID(flame ionization detector) sensor can be provided to scan the flow asthe flow enters the chambered baffle tank.

Iron is effectively removed by the system (97-99.4%). At a flow of270,000 liters per day and 40 mg/L total Fe, iron precipitates out, as afloculate at 10,800 gms or 23.8 lbs. of iron per day or about a ton per100 operating days.

If ultra-filtration/reverse osmosis treatment is needed to remove salt,the treatment would yield about one ton/day (2000 lbs) for reduction of30,000 ppm to 10,000 ppm TDS.

Flows of 6,000 to 60,000 gpd frac water:

TABLE III Partial UF/RO Treatment Input Output (as needed) TPH200-180,000 ug/L <2000 ug/L <1000 ug/L BTEX 100-9,000 ug/L <20 ug/L <10ug/L TDS 6,000-30,000 mg/L <20,000 mg/L <10,000 mg/L Iron 10-200 mg/L<.1 mg/L <.01 mg/L

Enhanced Reactive Ozone

Referring now to FIG. 9, a sparging arrangement 210 for use with plumes,sources, deposits or occurrences of contaminants, is shown. Thearrangement 210 is disposed in a well 212 that has a casing 214 with aninlet screen 214 a and outlet screen 214 b to promote a re-circulationof water into the casing 214 and through the surrounding ground/aquiferregion 216. The casing 214 supports the ground about the well 12.Disposed through the casing 214 are one or more multi-fluid diffusers,e.g., 50, 250′ (discussed in FIGS. 3 and 4) or alternatively in someapplications the multi-fluid diffuser 330 (FIG. 15).

The arrangement 210 also includes a first pump or compressor 222 and apump or compressor control 224 to feed a first fluid, e.g., a gas suchas an ozone/air or oxygen enriched air mixture, as shown, oralternatively, a liquid, such as, hydrogen peroxide or a hydroperoxide,via feed line 238 a to the multi-fluid diffuser 250. The arrangement 210includes a second pump or compressor 226 and control 227 coupled to asource 228 of a second fluid to feed the second fluid via feed line 2238b to the multi-fluid diffuser 250. A pump 230, a pump control 231, and asource 232 of a third fluid are coupled via a third feed 238 c to themulti-fluid diffuser 250.

The arrangement 210 can supply nutrients such as catalyst agentsincluding iron containing compounds such as iron silicates or palladiumcontaining compounds such as palladized carbon. In addition, othermaterials such as platinum may also be used.

The arrangement 210 makes use of a laminar multi-fluid diffuser 250(FIG. 11 or FIG. 4). The laminar multi-fluid diffuser 250 allowsintroduction of multiple, fluid streams, with any combination of fluidsas liquids or gases. The laminar multi-fluid diffuser 250 has threeinlets. One of the inlets introduces a first gas stream within interiorregions of the multi-fluid diffuser, a second inlet introduces a fluidthrough porous materials in the laminar multi-fluid diffuser 250, and athird inlet introduces a third fluid about the periphery of the laminarmulti-fluid diffuser 250. The fluid streams can be the same materials ordifferent.

In the embodiment described, the first fluid stream is a gas such as anozone/air mixture, the second is a liquid such as hydrogen peroxide, andthe third is liquid such as water. The outward flow of fluid, e.g.,air/ozone from the first inlet 252 a results in the liquid, e.g., thehydrogen peroxide in the second flow to occur under a siphon conditiondeveloped by the flow of the air/ozone from the first inlet 252 a.

Alternatively, the flows of fluid can be reversed such that, e.g.,air/ozone from the second inlet 252 a and the liquid, e.g., the hydrogenperoxide flow from first inlet, to have the ozone stream operate under asiphon condition, which can be used to advantage when the arrangement isused to treat deep deposits of contaminants. The ozone generatoroperating under a siphon condition is advantageous since it allows theozone generator to operate at optimal efficiency and delivery of optimalamounts of ozone into the well, especially if the ozone generator is acorona discharge type. In this embodiment, the third fluid flow iswater. The water is introduced along the periphery of the multi-fluiddiffuser 250 via the third inlet.

Referring to FIG. 10, an alternate arrangement 240 to produce the finebubbles is shown. A well casing 241 is injected or disposed into theground, e.g., below the water table. The casing 241 carries, e.g., astandard 10-slot well-screen 243. A laminar microporous diffuser 245 isdisposed into the casing 241 slightly spaced from the well screen 243. Avery small space is provided between the laminar microporous diffuser245 and the 10-slot well screen. In one example, the laminar microporousdiffuser 245 has an outer diameter of 2.0 inches and the inner diameterof the well casing is 2.0 inches. The laminar microporous diffuser 245is constructed of flexible materials (described below) and as thelaminar microporous diffuser 245 is inserted into the casing 241 itflexes or deforms slightly so as to fit snugly against the casing 241.In general for a 2 inch diameter arrangement a tolerance of about ±0.05inches is acceptable. Other arrangements are possible. The bottom of thecasing 241 is terminated in an end cap. A silicon stopper 247 isdisposed over the LAMINAR SPARGEPOINT® type of microporous diffuseravailable from Kerfoot Technologies, Inc. and also described in U.S.Pat. No. 6,436,285. The silicone stopper 247 has apertures to receivefeed lines from the pumps (as in FIG. 9, but not shown in FIG. 10).

Exemplary operating conditions are set forth in Table IV.

For In-situ Type Applications

TABLE IV Laminar Hydro- Water microporous Operating Ozone peroxide FlowRecirculation diffuser pressure Unit Air gm/day gal/day gal/min Wellswith screen (psi) Wall  3-5 cfm 144-430  5-50 1-3  1-4 1-8  0-30  mountPalletized 10-20 cfm 300-1000 20-200 1-10 1-8 1-16 0-100 Trailer 20-100cfm  900-5000  60-1000 1-50  1-20 1-40 0-350

Flow rates are adjusted to a pressure that offsets groundwater hydraulichead and formation backpressures. In general, pressures of, e.g., above40 psi ambient are avoided so as to prevent fracture or distortion ofmicroscopic flow channels. The percent concentration of hydroperoxide inwater is typically in a range of 2-20 percent, although otherconcentrations can be used. The flow is adjusted according to anestimate of the total mass of the contaminants in the soil and water. Ifhigh concentrations (e.g., greater than 50,000 parts per billion inwater or 500 mg/kg in soil) of the contaminants are present, sufficienthydroperoxides are added to insure efficient decomposition by theCriegee reaction mechanism or hydrogen peroxide to augment hydroxylradical formation.

Extremely fine bubbles from an inner surface of the microporous gas flowand water (including a hydroperoxide, e.g., hydrogen peroxide) aredirected by lateral laminar flow through the porous material or closedspaced plates (FIG. 10). The gas to water flow rate is held at a lowratio, e.g., sufficiently low so that the effects of coalescence arenegligible and the properties of the fluid remain that of the enteringwater.

Alternatively, the water flow is oscillated (e.g., pulsed), instead offlowing freely, both to reduce the volume of water required to shear,and maintain the appropriate shear force at the interactive surface ofthe gas-carrying microporous material. Johnson et al., SeparationScience and Technology, 17(8), pp. 1027-1039, (1982), described thatunder non-oscillating conditions, separation of a bubble at amicroporous frit surface occurs when a bubble radius is reached suchthat drag forces on the bubble equal the surface tension force πDδ, as:

${C_{D}\left\lbrack \frac{\rho\; U_{o}^{2}A_{p}}{2} \right\rbrack} = {\pi\; D\;\delta}$where C_(D) is the constant analogous to the drag coefficient, ρ is thefluid density, U₀ ² is the fluid velocity, A_(p) is the projected bubblearea, π is pi, 3.14, a constant, δ is the gas-water surface tension, andD is the pore diameter of the frit. A bubble is swept from themicroporous surface when the bubble radius is reached such that thedynamic separating force due to drag equals the retention force due tosurface tension. Bubble distributions of 16 to 30μ (micron) radius and 1to 4×10⁶ bubbles/min can be produced with a gas flow rate of 8 cm³/minand rotational water flow rates of 776 cm³/min across a microporoussurface of μ (micron) pore size with a 3.2 cm diameter surface area. Ifthe flow of liquid is directed between two microporous layers in afluid-carrying layer, not only is a similar distribution of microbubblesize and number of microbubbles produced, but, the emerging bubbles arecoated with the liquid which sheared them off.

In order to decompose certain dissolved recalcitrant compounds, astronger oxidation potential is necessary for reaction. Ozone in thedissolved form is a recognized strong reagent for dissolved organics buthas a short 15 to 30 minute half-life. By reducing the size of gasbubbles to the point where the vertical movement is very low, ozone in agaseous form can co-exist with dissolved forms as a homogenous mixture.The half-life of gaseous ozone is much longer than dissolved forms,ranging 1 to 20 hours. As the bubbles of ozone become nano size, thesurface area to volume ratio exceeds 1.0 and approaches ranges of 5 to30, thus providing an exceptional capacity to withdraw smaller saturatedmolecules towards the surfaces from Henry's partitioning. However, thebehavior of the nanobubble ozone indicates a new form of ozone where theresonating triatom orients itself to form a membrane which changessurface tension within the water. This allows the production ofnano-sized bubbles of ozone which cannot be produced by using air ornitrogen gas under similar conditions of gas flow shear and pressure.

Characteristics of varying sizes bubbles entrapping ozone are depictedin Table V.

TABLE V Diameter Surface Area Volume Surface Area/ (microns) 4πr² 4/3πr³ Volume 200 124600 4186666 .03 20 1256 4186 0.3 2 12.6 4.2 3.2 .2 .13.004 32

In addition to using a continual flow of fluid to shear the outsidesurfaces on the cylindrical generator, the liquid can be oscillated(pulsed) at a frequency sufficient to allow for fluid replacement in themicroporous diffuser, for the volume of liquid removed as coatings onthe bubbles, but not allowing interruption of the liquid/bubble columnon its way to the surface (or through a slit, e.g., well screen slot).To avoid coalescing of the microbubbles, a continual stream of micro tonanobubbles, actually coated with the peroxide liquid is emitted fromthe surface of the laminated generator.

Some examples of gas flows and liquid volumes are listed below in TableVI for each of the examples described in FIGS. 1 and 2.

TABLE VI Per 8 cm surface area, (5 μm (micron) porosity) RotationalWater Mean Flow rates Bubble size Bubble size range Rotative Frequency10 cm³/min gas (μm) (μm) bubbles/min 250 cm³/min 30 16-60  4 × 10⁶ 500cm³/min 20 16-50  7 × 10⁶ 800 cm³/min 15  8-30 15 × 10⁶ 3500 cm³/min 10 5-15 30 × 10⁶ 3000 cm³/min 5  .5-10 50 × 10⁶ 5000 cm³/min 2 .2-6  80 ×10⁶ 5000 cm³/min <1 .1-5  100 × 10⁶ 

For an equivalent LAMINAR SPARGEPOINT® type of microporous diffuseravailable from Kerfoot Technologies, Inc. (formally KV-Associates (2INCH OUTER DIAMETER)

For Laminar Spargepoint®

Porous Surface Area is 119 sq. in. (771 sq. cm.)

Gas flow 25000 cm³/min (25 l/min) or (0.8825 cu. ft/min)=52.9 cu.ft./hr.

(20 cfm)=1200 cu. ft./hr

(L×0.264=gallons)

Liquid flow

If continuous: 625 l/min (165 gallons/min) or 2000 gallons/day

If oscillate: 5 gallons/day

The liquid is supplied with a Pulsafeeder® pulsing peristaltic pump tooscillate the liquid (5 psi pulse/sec) and to deliver an adjustable 0.1to 10 liters/hour (7 to 60 gallons/day). Table VII depicts exemplary gasflow and water rates.

TABLE VII TWO LAMINAR MICROPOROUS MATERIALS OSCILLATING GAS GAS FLOWWATER FLOW BUBBLE SIZE FREQUENCY 50 scf 200-800 ccm/min (μm)Bubbles/min. 1 cfm 1 L/min (.26 gallons/min 5 μm 10 × 10⁸ 3 cfm 3 L/min(.78 gallons/min 5 μm 10 × 10⁸ 30 cfm¹  30 L/min (7.8 gallons/min  5 μm10 × 10⁸ (2 inch 800 sq. cm. LAMINAR SPARGEPOINT ® type of microporousdiffuser available from Kerfoot Technologies, Inc.¹ ¹Would require ten(10) LAMINAR SPALRGEPOINT ® type of microporous diffuser for operation,or increase length or diameter of the microporous diffuser).

For insertion of the LAMINAR SPARGEPOINT® type of microporous diffuserinto well screens or at depth below water table, the flow of gas andliquid is adjusted to the back pressure of the formation and, for gasreactions, the height (weight) of the water column. At ambientconditions (corrected for height of water column), the liquid fractionis often siphoned into the exiting gas stream and requires no pressureto introduce it into the out flowing stream. The main role of anoscillating liquid pump is to deliver a corresponding flow of liquid tomatch a desired molar ratio of ozone to hydrogen peroxide for hydroxylradical formation as:2O₃+H₂O₃=2OH.+3O₂

Set out below are different operating conditions for different types ofsystems available from Kerfoot Technologies, Inc. (formallyKV-Associates, Inc.) Mashpee Mass. Other systems with correspondingproperties could be used.

Wallmount Unit Pressure range, injection: 10 to 40 psi Gas flow: 1-5Scfm (50 to 100 ppmv ozone) Liquid range: .03-.5 gallons/hr. (55 gallontank) (3 to 8% peroxide). Shearing fluid (water) Palletized unitsPressure range-injection: 10 to 100 psi Gas flow: 0-20 cfm (50 to 2000ppmv ozone) Liquid range: 0-5 gallons/hr (3 to 9% peroxide) Shearingfluid (water) Trailer units Pressure range-injection: 10 to 350 psi Gasflow: 0-100 cfm (50 to 10,000 ppmv ozone) Liquid range: 0-20 gallons/hr(3 to 9% peroxide) Shearing fluid (water)

The process involves generation of extremely fine microbubbles(sub-micron in diameter up to less than about 5 microns in diameter)that promote rapid gas/gas/water reactions with volatile organiccompounds. The production of microbubbles and selection of appropriatesize distribution optimizes gaseous exchange through high surface areato volume ratio and long residence time within the material to betreated. The equipment promotes the continuous or intermittentproduction of microbubbles while minimizing coalescing or adhesion.

The injected air/ozone combination moves as a fluid of such fine bubblesinto the material to be treated. The use of microencapsulated ozoneenhances and promotes in-situ stripping of volatile organics andsimultaneously terminates the normal reversible Henry's reaction.

The basic chemical reaction mechanism of air/ozone encapsulated inmicron-sized bubbles is further described in several of my issuedpatents such as U.S. Pat. No. 6,596,161 “Laminated microporousdiffuser”; U.S. Pat. No. 6,582,611 “Groundwater and subsurfaceremediation”; U.S. Pat. No. 6,436,285 “Laminated microporous diffuser”;U.S. Pat. No. 6,312,605 “Gas-gas-water treatment for groundwater andsoil remediation”; and U.S. Pat. No. 5,855,775, “Microporous diffusionapparatus” all of which are incorporated herein by reference.

The compounds commonly treated are HVOCs (halogenated volatile organiccompounds), PCE, TCE, DCE, vinyl chloride (VC), EDB, petroleumcompounds, aromatic ring compounds like benzene derivatives (benzene,toluene, ethylbenzene, xylenes). In the case of a halogenated volatileorganic carbon compound (HVOC), PCE, gas/gas reaction of PCE toby-products of HCl, CO₂ and H₂O accomplishes this. In the case ofpetroleum products like BTEX (benzene, toluene, ethylbenzene, andxylenes), the benzene entering the bubbles reacts to decompose to CO2and H2O. In addition, through the production of hydroxyl radicals (.OH)or perhydroxyl radicals (.OOH) or atomic oxygen O (³P) from sonicenhancement, additional compounds can be more effectively attacked, likeacetone, alcohols, the alkanes and alkenes.

Also, pseudo Criegee reactions with the substrate and ozone appeareffective in reducing saturated olefins like trichloro ethane(1,1,1-TCA), carbon tetrachloride (CCl₄), chloroform and chlorobenzene,for instance.

Other contaminants that can be treated or removed include hydrocarbonsand, in particular, volatile chlorinated hydrocarbons such astetrachloroethene, trichloroethene, cisdichloroethene,transdichloroethene, 1-1-dichloroethene and vinyl chloride. Inparticular, other materials can also be removed including chloroalkanes,including 1,1,1 trichloroethane, 1,1, dichloroethane, methylenechloride, and chloroform, O-xylene, P-xylene, naphthalene andmethyltetrabutylether (MTBE) and 1,4 Dioxane.

Ozone is an effective oxidant used for the breakdown of organiccompounds in water treatment. The major problem in effectiveness is thatozone has a short lifetime. If ozone is mixed with sewage containingwater above ground, the half-life is normally minutes. To offset theshort life span, the ozone is injected with multi-fluid diffusers 50,enhancing the selectiveness of action of the ozone. By encapsulating theozone in fine bubbles, the bubbles would preferentially extract volatilecompounds like PCE from the mixtures of soluble organic compounds theyencountered. With this process, volatile organics are selectively pulledinto the fine air bubbles. The gas that enters a small bubble of volume(4πr³) increases until reaching an asymptotic value of saturation.

The following characteristics of the contaminants appear desirable forreaction:

Henry's Constant: 10⁻¹ to 10⁻⁵ atm-m³/mol Solubility: 10 to 10,000 mg/lVapor pressure: 1 to 3000 mmHg Saturation concentration: 5 to 100 g/m³

The production of micro to nano sized bubbles and of appropriate sizedistribution are selected for optimized gas exchange through highsurface area to volume ratio and long residence time within the area tobe treated.

Referring now to FIG. 11, a multi-fluid diffuser 250 is shown. Themulti-fluid diffuser 250 includes inlets 252 a-252 c, coupled toportions of the multi-fluid diffuser 250. An outer member 255 surroundsa first inner cylindrical member 256. Outer member 255 provides an outercylindrical shell for the multi-fluid diffuser 250. First innercylindrical member 256 is comprised of a hydrophobic, microporousmaterial. The microporous material can has a porosity characteristicless than 200 microns in diameter, and preferable in a range of 0.1 to50 microns, most preferable in a range of 0.1 to 5 microns to producenanometer or sub-micron sized bubbles. The first inner member 256surrounds a second inner member 260. The first inner member 256 can becylindrical and can be comprised of a cylindrical member filled withmicroporous materials. The first inner member 256 would have a sidewall56 a comprised of a large plurality of micropores, e.g., less than 200microns in diameter, and preferable in a range of 0.1 to 50 microns,most preferable in a range of 0.1 to 5 microns to produce nanometer orsub-micron sized bubbles.

A second inner member 260 also cylindrical in configuration is coaxiallydisposed within the first inner member 256. The second inner member 260is comprised of a hydrophobic material and has a sidewall 260 acomprised of a large plurality of micropores, e.g., less than 200microns in diameter, and preferable in a range of 0.1 to 50 microns,most preferable in a range of 0.1 to 5 microns to produce nanometer orsub-micron sized bubbles. In one embodiment, the inlet 252 a issupported on an upper portion of the second inner member 260, and inlets252 b and 252 c are supported on a top cap 252 and on a cap 253 on outermember 255. A bottom cap 259 seals lower portion of outer member 255.

Thus, proximate ends of the cylindrical members 256 and 260 are coupledto the inlet ports 252 b and 252 a respectively. At the opposite end ofthe multi-fluid diffuser 250 an end cap 254 covers distal ends ofcylindrical members 256 and 260. The end cap 254 and the cap 252 sealthe ends of the multi-fluid diffuser 250. Each of the members 255, 256and 260 are cylindrical in shape.

Member 255 has solid walls generally along the length that it shareswith cylindrical member 260, and has well screen 257 (having holes withdiameters much greater than 200 microns) attached to the upper portionof the outer member. Outer member 255 has an end cap 59 disposed overthe end portion of the well-screen 257. The multi-fluid diffuser 250also has a member 272 coupled between caps 254 and 257 that provide apassageway 273 along the periphery of the multi-fluid diffuser 250.Bubbles emerge from microscopic openings in sidewalls 260 a and 256 a,and egress from the multi-fluid diffuser 250 through the well screen 257via the passageway 273.

Thus, a first fluid is introduced through first inlet 252 a inside theinterior 275 of third member 260, a second fluid is introduced throughthe second inlet 252 b in region 71 defined by members 256 and 260, anda third fluid is introduced through inlet 252 c into an outer passageway273 defined between members 253, 255, 256, and 259. In the system ofFIG. 9, the first fluid is a gas mixture such as ozone/air that isdelivered to the first inlet through central cavity 275. The secondfluid is a liquid such as hydrogen peroxide, which coats bubbles thatarise from the gas delivered to the first inlet, and the third fluid isa liquid such as water, which is injected through region 273 and acts asa shearing flow to shear bubbles off of the sidewall 256 a. By adjustingthe velocity of the shearing fluid, bubbles of very small size can beproduced (e.g., sub-micron size). Of course adjusting the conditions andporosity characteristics of the materials can produce larger sizebubbles.

Referring to FIG. 12, an alternative embodiment 2250′ has thecylindrical member 256 terminated along with the member 260 by a pointmember 278. The point member 278 can be used to directly drive themulti-fluid diffuser into the ground, with or without a well. The pointmember can be part of the cap 259 or a separate member as illustrated.

The multi-fluid diffuser 250 or 250′ is filled with a microporousmaterial in the space between members 256 and 260. The materials can beany porous materials such as microbeads with mesh sizes from 20 to 200mesh or sand pack or porous hydrophilic plastic to allow introducing thesecond fluid into the space between the members 256 and 260.

In operation, the multi-fluid diffuser 250 is disposed in a wet soil oran aquifer. The multi-fluid diffuser 250 receives three fluid streams.In one embodiment, the first stream that is fed to the inlet 252 a is aliquid such as water, whereas second and third streams that feed inlets52 b and 52 c are hydrogen peroxide and a gas stream of air/ozone. Themulti-fluid diffuser 250 has water in its interior, occasioned by itsintroduction into the aquifer. The air ozone gas stream enters themulti-fluid diffuser 250 and diffuses through the cylindrical member 256as trapped microbubbles into the space occupied by the microporousmaterials where a liquid, e.g., hydrogen peroxide is introduced to coatthe microbubbles. The liquid stream through the microporous materials isunder a siphon condition occasioned by the introduction of water throughthe periphery of the multi-fluid diffuser 250. The flow of water inadditional to producing a siphoning effect on the liquid introducedthrough inlet 252 b also has a shearing effect to shear bubbles from themicroporous sides of the cylindrical member 260, preventing coalescingand bunching of the bubbles around micropores of the cylindrical member260. The shearing water flow carries the microbubbles away through thewell screen disposed at the bottom of the multi-fluid diffuser 250.

Referring now to FIGS. 13A, 13B, exemplary construction details for theelongated cylindrical members of the multi-fluid diffusers 250 or 250′and the laminar microporous diffuser 245 are shown. As shown in FIG.13A, sidewalls of the members can be constructed from a metal or aplastic support layer 291 having large (as shown) or fine perforations291 a over which is disposed a layer of a sintered i.e., heat fusedmicroscopic particles of plastic to provide the micropores. The plasticcan be any hydrophobic material such as polyvinylchloride,polypropylene, polyethylene, polytetrafluoroethylene, high-densitypolyethylene (HDPE) and ABS. The support layer 291 can have fine orcoarse openings and can be of other types of materials.

FIG. 13B shows an alternative arrangement 294 in which sidewalls of themembers are formed of a sintered i.e., heat fused microscopic particlesof plastic to provide the micropores. The plastic can be any hydrophobicmaterial such as polyvinylchloride, polypropylene, polyethylene,polytetrafluoroethylene, high-density polyethylene (HDPE) andalkylbenzylsulfonate (ABS). Flexible materials are desirable if thelaminar microporous diffuser 245 is used in an arrangement as in FIG.10.

The fittings (i.e., the inlets in FIG. 10,) can be threaded and/or areattached to the inlet cap members by epoxy, heat fusion, solvent orwelding with heat treatment to remove volatile solvents or otherapproaches. Standard threading can be used for example NPT (nationalpipe thread) or box thread e.g., (F480). The fittings thus are securelyattached to the multi-fluid diffusers 250 in a manner that insures thatthe multi-fluid diffuser 250 can handle pressures that are encounteredwith injecting of the air/ozone.

Referring to FIGS. 14 and 6A, a septic system 310 is shown. The septicsystem includes a septic tank 312, coupled to a leach field 314 havingperforated distribution pipes or chambers (not shown) to distributeeffluent from the tank 312 within the leach field. The tank can becoupled to a residential premises or a commercial establishment. Inparticular, certain types of commercial establishments are of particularinterest. These are establishments that produce effluent streams thatinclude high concentration of pharmaceutical compounds, such aspharmaceutical laboratories and production facilities, hospitals andnursing homes.

The leach field 314 is constructed to have an impervious pan, 116 spacedfrom the distribution pipes by filter media 322 (FIG. 6A). The pan isprovided to intercept and collect water from filter media 322 in theleach field after treatment and deliver the water and remainingcontaminants via tube 317 to an ozone treatment tank 318. The water maystill have high concentrations of nitrogen containing compounds andpharmaceutical compounds. The ozone treatment tank 318 is disposedbetween the leach field 320 and the final leach field 314. The firstphase of treatment may also employ a denitrification system with 1 or 2leaching fields. The ozone treatment tank 318 temporarily stores thecollected water from the pan 316. The ozone treatment tank 318 has anin-situ microporous diffuser, such as those described in FIGS. 11, 12 orreceives a solution from a diffuser 330 described in FIG. 15, below, toinject air/ozone in the form of extremely small bubbles, e.g., less than20 microns and at higher ozone concentrations. In addition, the diffuser(FIG. 15) is configured to supply the air/ozone in stream of water thatcomes from an external source rather than using the effluent from theleach field 314 to avoid clogging and other problems.

In another embodiment (FIG. 6A), the bubble generator system is disposedoutside of the tank 318 and has a tube 323 that feeds a porous mixingchamber 325 (static or with a stirrer) at the bottom of the tank 380.Acoustic probes, e.g., 321 can be disposed within the tips of the tubes,as shown in FIG. 14B at the egress of tube 323 and as shown in phantomat the ingress of tube 323, to further agitate and shape the bubbles.Other embodiments as shown in FIG. 16 can have the bubble generatordisposed in the tank 318.

Referring now to FIG. 15, a diffuser 330 includes a bubble generator 332disposed within a container, e.g., a cylinder 334 having impervioussidewalls, e.g. plastics such as PVDF, PVC or stainless steel. Inembodiments with magnetic stirrers, the walls of the container, at leastthose walls adjacent to the magnetic stirrer are of non-magneticmaterials.

The bubble generator 332 is comprised of a first elongated member, e.g.,cylinder 332 a disposed within a second elongated member, e.g., cylinder332 c. The cylinder 332 a is spaced from the cylinder 332 c bymicroporous media, e.g., glass beads or sintered glass having particlesized of, e.g., 0.01 microns to 0.1 microns, although others could beused. Fittings 333 a and 333 b are disposed on a cap 333 to receivedfluid lines (not numbered). A bottom cap 335 seals end portions of thecylinders 332 a and 332 b. The cylinders 332 a and 332 c are comprisedof sintered materials having microporosity walls, e.g., average poresizes of less than one micron or (1 to 0.25 microns). The sinteredcylinder 332 b or bead material with diameters of 0.2 to 20 microns,with a porosity of 0.4 to 40 microns, receives liquid. Granularmaterials 349, such as sand, can be included along with a screen 347, asshown to assist with formation of fine bubbles. The screen 347 wouldneed to have openings small enough to keep the sand in the diffuser 350.

Disposed in a lower portion of the cylindrical container 334 is astirring chamber 340 provided by a region that is coupled to thecylindrical container 334 via a necked-down region 338. This region, foruse with a magnetic stirrer, is comprised on non-magnetic materials,other that the stirring paddle. Other arrangements are possible such asmechanical stirrers. The stirring chamber supports a paddle that stirsfluid that exits from the necked down region 338 of cylindricalcontainer 334 and which in operation causes a vortex to form at thebottom of the necked down region 138 and below the generator 332. Amagnetic stirrer 344 is disposed adjacent the stirring chamber 340.Alternatively the stirrer can be as shown as the stirrer with electriccoil (not numbered).

A second necked down region 346 couples the stirring chamber 340 to anexit port 349. Disposed in the exit port 349 is an adjustable valve 348.The adjustable valve is used to adjust the fluid flow rate out of thediffuser 330 to allow the egress rate of fluid out of the diffuser 330to match the ingress rate of fluid into the diffuser 330. As shown indetail in FIG. 15A the stirrer 342 has shafts that are coupled to a pairof supports 141 a within the stirring chamber 140, via bearings 342 b orthe like. Other arrangements are possible. The supports are perforated,meaning that they have sufficient open area so as not to inhibit flow offluids. The supports can be perforated disks, as shown, or alternativelybars or rods that hold the bearings and thus the shafts for stirrer inplace.

Referring now to FIG. 16, the diffuser 330 is disposed in the ozonecontact tank 330. In operation, water or another liquid (e.g., HydrogenPeroxide especially for sparging applications of FIGS. 1 and 2) isdelivered to one port 333 c of the generator 332 via tubing, notreferenced. A dry air+Ozone stream is delivered to the other port 333 aof the generator 332. As the air+ozone stream exits from walls of thecylinder 332 a the air+ozone is forced out into the microporous media332 b where the air+ozone come in contact with the liquid delivered toport 332 c. The liquid meets the air+ozone producing bubbles ofair+ozone that are emitted from the bubble generator 332, as part of abubble cloud of the stream of water.

The stirring action provided by the stirrer 140 produces a vortex abovethe stirrer 140 with cavitation of the liquid stream, producing nanosize bubbles. The ideal liquid velocity is maintained at greater than500 cc/min across a less than 1 micron porosity surface area of 10 cm².The stirrer maintains a rotational flow velocity of greater than 500cm³/min per 8 cm surface area, maintaining a porosity less than 5microns.

In one arrangement, the sidewalls of the tubes have a porosity of 1 to0.25 μm (microns), and the interstitial portion that receives liquid andhas glass beads of diameter 0.1 mm or less. The sidewalls can be ofsintered glass, sintered stainless steel, a ceramic or sinteredplastics, such as polyvinyl chloride (PVC), high density polyethylene(HDPE), polyfluorocarbons (PVDF), Teflon.

The diffuser 330 can be continuously fed a water stream, which producesa continuous outflow of submicron size bubbles that can be directedtoward a treatment, which is an advantage because the bubble generator332 inside the diffuser 330 is not exposed to the actual waters beingtreated and therefore the generator 332 will not foul in the water beingtreated.

Referring now to FIG. 17, a depiction of a unique bubble arrangementthat occurs under specified conditions with gaseous ozone providedwithin extremely fine bubbles at relatively high ozone concentrations,e.g., ozone from 5 to 20% concentration with the balance air e.g.,oxygen and nitrogen is shown. The arrangement has ozone, which has apolar structure of tri-atomic oxygen (ozone), forming constructs ofspherical reactive “balls.” As depicted, for a single slice of such aspherical ball, the ozone at the interface boundary of the gas with thewater has a surface in which the ozone molecule is aligned and linked.These constructs of ozone allow very small 20 to 20,000 nanometerbubble-like spheres of linked ozone molecules to form in subsurfacegroundwater, which are not believed possible for simple bubbles of airalone or air with ozone at lower concentrations, due to high surfacetension.

The structure shown in FIG. 17 contains gaseous ozone and air on theinside and an ozone membrane arrangement like a micelle on the gas-waterinterface, as shown.

As bubbles of ozone become smaller and smaller, e.g., from micron tonano size bubbles, the ozone content in the bubbles aligns, meaning thatthe ozone molecules on the surface of the bubble, i.e., adjacent water,orient such that the predominantly the outer oxygen atoms (negativecharge) align outwards, whereas the center oxygen atom (positive orneutral charge) aligns inward.

The interface between the aligned ozone molecules and surrounding waterprovides a reactive skin zone or interface. In this structure it isbelieved that the ozone “sticks” to the surface film of the water tore-orientate itself. In this orientation the ozone can resonate betweentwo of the four theorized resonance structures of ozone, namely type IIand type III (See FIG. 17A), whereas when the ozone comes in contactwith a contaminant, it may switch to the more reactive forms types IVand V donating electrons to decompose the contaminate. A terminal oxygenatom thus can become positively charged so as to act as an electrophilicto attack a nucleophilic site of an organic molecule. All of the fourresonance structures have a negatively charged terminal oxygen atomcausing ozone to act as a nucleophile to attack an electrophilic site onan organic molecule. Ozone acting as a nucleophile can attack electrondeficient carbon atoms in aromatic groups. Structures IV and V whereozone acts like a 1,3 dipole undergoes 1,3 dipole cycloaddition withunsaturated bonds to result in a classical formation of the Criegeeprimary ozonide.

The membrane (skin-like) structure of the ozone depicted in FIG. 17 canbe a formidable resonance reactor because as volatile organic compoundsare pulled into the structure (according to Henry's law) when thecompounds come in contact with the skin-like structure electron flow canquickly proceed for substitution reactions. With excess ozone gas in thebubble, replacement of the lost ozone in the skin layer of the bubble isquick.

The resonance hybrid structure of the ozone molecule has an obtuse angleof 116° 45″±35″ and an oxygen bond length of 1.27 Å (about 0.13 nm).Trambarolo, et al., (1953) explained that the band length wasintermediate between the double bong length in O₂ (1.21 Å) and thesingle bond length in hydrogen peroxide H₂O₂ (1.47 Å). The resonancehybrid can be thought of orienting with the negative (−) charge outwardsand the positive charge inwards with linkage occurring similar to Kekuléstructure of carbon by alternating resonance forms among the alignedbonding electrons. This structure of the ozone changes surface tensionwith water to produce extremely fine micro to nanobubbles unable to beformed with air (nitrogen/oxygen gas) alone.

The surface properties of the ball structure promote the formation of areactive surface equivalent to hydroxyl radicals or found with thermaldecomposition of ozone in collapsing cavitation bubbles of sonolyticsystems. The reactivity with organic contaminants such as alkanes or 1,4Dioxane may approach or exceed the reactivity of ozone and peroxideaddition, known to produce hydroxyl radicals.

The basis for this discovery includes observed changes in surfacetension, allowing smaller and smaller bubbles with increasing ozoneconcentration. In addition, the equivalent reactivity of the nano-microbubbles with that of hydroxyl radical formers is greater. For example,the reactivity is unquenched with carbonate addition where hydroxylradical reactions are quickly quenched. In addition, the ozone has anincreased capacity to react with ether-like compounds such as MTBE and1,4 Dioxane compared to what would be expected.

For example, Mitani, et al., (2001) determined in a laboratory studythat if O₃ alone were used to remediate MTBE, then increased residencetime, temperature, or O₃ concentration was necessary to completelyoxidize MTBE to carbon dioxide. Generally, it is assumed that theinitial OH. attack on MTBE by H. abstraction occurs at either methoxygroup or any of the three methyl groups. The O—H bond energy is higherthan that of the C—H bond of an organic compound, resulting in OH.indiscriminately abstracting hydrogen from organic compounds (Mitani, etal., 2001).

The direct bubbling of ozone from the microporous diffuser 250 (FIGS.11, 12), where a liquid is forced through simultaneously with ozone gasor the diffuser 330 (FIG. 15) produces stable submicron-sized bubbles.The mean size of the bubbles can be checked by measuring the rise timeof an aerosol-like cloud of such bubbles in a water column.

The unique spherical formation would explain a certain amount ofpreviously unexplainable unique reactivities (with alkane fractions, forexample). The reactivity of the microfine ozone bubbles with linear andbranched alkanes would be a possible explanation for such low ratios ofmolar reactivities.

The size of bubbles would run from twenty nanometers (nm) or smaller upto about 20 microns (20,000 nm) in size. At 20 microns, the ozoneconcentration would be in a range of about 1% up to a maximum of 20%,whereas at the smaller size bubbles can be less, e.g., from 1% to 20% atthe higher end to less than 1% because of higher surface area. Anotherrange would be twenty nanometers (nm) or smaller up to about 1 micron insize with 1 to 10% ozone concentration. Normally, a 20 micron sizedporosity microporous diffuser will produce bubbles of about 50 micronsin diameter and thus smaller porosity microporous diffusers would beused or the arrangements discussed below to produce the smaller bubbles.

Possibly the entire surface area of the bubbles need not be occupiedcompletely with the ozone molecules in order to start observing thiseffect. At as little as 10% (85% oxygen, balance nitrogen) of thesurface area of the bubbles need be covered by ozone in order for theeffect to start occurring.

The oxygen atoms in the ozone molecule have a negative charge whichallows the oxygen atoms to break into smaller bubbles in water bychanging surface tension. The ozone undergoes a structural change byorienting the negative and positive charges. The ozone structures haveresonance structure and the ozone in the form of a gas with watermolecules, could preferentially take an orientation that places thepolar bonded oxygen atoms towards the water and the central oxygen atomstowards the middle of the bubbles, with the interior of the bubblesfilled with ozone and air gases.

Certain advantages may be provided from this type of structure withrespect to treating organic contaminants.

Because of the resonant structure of ozone, this structure appears to beinherent more reactivity than is normally associated with dissolvedmolecular ozone. Conventionally mixing hydrogen peroxide with ozone isthought to produce hydroxyl radicals and a concomitant increase inoxidative potential. When formed in water, however, the reactivity ofhydrogen peroxide and ozone with certain materials appears to be farsuperior to that of normal hydroxyl radical formation. This can beparticularly event with ether-like compounds and with simple carbonlineages like the octanes and hexanes.

The level of reactivity cannot be explained simply by increases in thesurface to volume ratio that would occur when ozone is placed in smallerand smaller structures. The reactivity that occurs appears to be aheightened reactivity where the ozone itself is competing with ozoneplus peroxide mixtures, which are normally thought to create thehydroxyl radical which has usually at least two orders of magnitudefaster reactivity than dissolved molecular ozone. It is entirelypossible that through the reinforcement of the resonation of themolecules of the oxygen that the way the ozone is arranged the ozone candirect more efficient reaction upon contact than individualtri-molecular ozone. Thus, less moles of ozone are needed to produce areaction with a particular compound. This form of ozone has areactive-like surface structure.

As the bubbles get finer and finer it is difficult to measure aconsistent rate of rise because they go into motion and are bouncedaround by the water molecules. Secondarily, individual bubbles will“draft,” once one moves vertically, resulting in an accelerated line ofbubbles. The nanobubbles show exceptional stability.

Pharmaceutical compounds are a particular good target for this enhancedreactive ozone, because pharmaceutical compounds are difficult compoundsto decompose.

Referring to FIG. 18, a nanobubble generator 350 that can be deployed infield operations is shown. The nanobubble generator 350 includes anozone generator 352 fed via, e.g., dry air or oxygen, a nanobubblesolution generator 354 fed liquid, e.g., water or hydrogen peroxide andozone/air or ozone/oxygen from a compressor 356. Liquid is output fromthe nanobubble solution generator 354 and includes a cloud ofnanobubbles, and is delivered to a bank of solenoid controlled valves358 to feed tubes 359 that can be disposed in the contact tanks (FIG.6A. or wells). The feed tubes 359 can have acoustic or sonic probes 123disposed in the tips, as shown. A controller/timer 153 controls thecompressor and solenoid control valves. A excess gas line 355 isconnected via a check valve 157 between nanobubble solution generator354 and the line from the ozone generator to bleed off excess air fromthe nanobubble solution generator 354.

A number of embodiments of the invention have been described. Treatmentparameters given above are exemplary and other parameters may providesuitable results. In addition other techniques may be used to producethe desired size of nanobubbles. In some applications the bubbles neednot be nano size but could be micro size bubbles, e.g., generally lessthat about 500 microns and in particular less than 200 microns. Otherexamples as shown in FIG. 8 have the treatment apparatus re-injectingwater into the same well or for discharge as discussed above. Moreover,other techniques could be used to produce the water with the elevatedORP. For instance, rather than using frac water, water can be treated toprovide, e.g., alkanes, and thereafter that water can be treated withozone or ozone/hydrogen peroxide to provide water with the elevated ORP.Other techniques are possible, such as coating micro to nanobubbles withpersulfate, modified Fenton's Reagent, sodium percarbonate, or othersurfaces which would enhance formation of hydroxyl radicals. Therefore,it will be understood that various modifications may be made withoutdeparting from the spirit and scope of the invention. In addition, othertechniques can be used to increase the ORP reactivity of the frac water.Accordingly, other embodiments are within the scope of the followingclaims.

1. A method comprising: receiving water that was introduced into andrecovered from an earth formation, with the recovered water comprisingsuspended hydrocarbon product in the water; treating the recovered waterto remove substantial amounts of the suspended hydrocarbon product byexposing the recovered water to ozone/air bubbles having a size lessthan 500 microns to provide the treated recovered water; andre-introducing the treated recovered water with an elevatedoxidation/reduction potential (ORP) of at least 100 mv into the earthformation.
 2. The method of claim 1 wherein the formation includes shaledeposits.
 3. The method of claim 1 wherein the suspended hydrocarbonproduct comprises alkanes and alkenes.
 4. The method of claim 1 whereinre-introducing further comprises: re-introducing the treated recoveredwater with an ORP in a range of 150 mv to 1000 mv into the formation toassist in recovery of additional hydrocarbon deposits in the formation;recovering the re-introduced, treated recovered water; and removingadditional hydrocarbon product from the recovered re-introduced, treatedrecovered water.
 5. The method of claim 1 further comprising: exposingthe recovered water to a fluid comprising ozone gas in bubbles having asize less than 200 microns.
 6. The method of claim 1 further comprising:exposing the recovered water to a fluid comprising ozone gas in bubbleshaving a size less than 200 microns and hydrogen peroxide.
 7. The methodof claim 1 further comprises: exposing the recovered water to a fluidstream of microbubbles entrapping ozone gas in bubbles having a sizeless than 1 micron.
 8. The method of claim 1 further comprises: exposingthe recovered water to a fluid stream of hydrogen peroxide coatedmicrobubbles entrapping ozone gas in bubbles having a size less than 1micron.
 9. The method of claim 1 wherein re-introducing the treatedrecovered liquid with the ORP into a formation reintroduces the treatedrecovered water into the same formation that the recovered water wasrecovered from.
 10. The method of claim 1 wherein re-introducing thetreated recovered water with the ORP into a formation reintroduces thetreated recovered water into a different formation than the recoveredwater was recovered from.
 11. The method of claim 1 wherein thereintroduced, treated recovered water has an ORP in a range of 150 mv to1000 mv.
 12. A method of hydrocarbon recovery, the method comprising:introducing water into a formation; recovering the introduced water,with the recovered, introduced water comprising hydrocarbon product;treating the recovered water to remove portions of hydrocarbon productsuspended in the water, by exposing the recovered water to a fluidstream of hydrogen peroxide coated bubbles entrapping ozone gas;re-introducing the treated recovered water back into a formation; andrecovering additional water from the formation with the additional watercomprising additional hydrocarbon product that was liberated from theformation.
 13. The method of claim 12 wherein the suspended hydrocarbonproduct comprises alkanes and alkenes.
 14. The method of claim 12wherein the bubbles have a diameter in a range of about 0.05 microns toabout 200 microns.
 15. The method of claim 12 further comprisingpre-treating the recovered introduced liquid to remove substantialportions of hydrocarbon product leaving substantially suspendedhydrocarbon product in the liquid.
 16. A method of treating fracturewater, the method comprising: recovering introduced liquid from aformation, the recovered introduced liquid comprising water andsuspended hydrocarbon product; treating the recovered liquid to removesubstantial amounts of the suspended hydrocarbon product, in part by:exposing the recovered water to bubbles trapping air/ozone with thebubbles having a bubble size in a range of 0.05 to 200 microns.
 17. Themethod of claim 16 wherein treating comprises allowing the recoveredliquid to be held to permit lighter product to be skimmed off of theproduct, prior to exposing the water to the bubbles.
 18. The method ofclaim 16 wherein the suspended hydrocarbon product comprises alkanes andalkenes.
 19. The method of claim 16 wherein treating further comprises:holding the recovered liquid to permit heaver constituents to settlefrom the recovered liquid.
 20. The method of claim 16 wherein treatingfurther comprises: allowing the recovered liquid to be held to permitlighter product to be skimmed off of the product; and holding therecovered liquid to permit heaver constituents to settle from therecovered liquid prior to exposing the recovered liquid to a fluidcomprising ozone gas and hydrogen peroxide.
 21. The method of claim 16wherein treating further comprises: exposing the recovered liquid to afluid stream of hydrogen peroxide coated microbubbles entrapping ozonegas.
 22. The method of claim 16 wherein the recovered liquid aftertreatment by the ozone is essentially water that can be discharged intosurface waters.
 23. The method of claim 16 further comprising deliveringthe treated, recovered liquid after treatment by the ozone to a holdingarea to reduce the ORP until the water can be discharged.